Sometimes what you see isn’t necessarily what you get.Take the December Investor Movement Index, or the IMX. At first glance, it looks like retail traders continued their fledgling retreat from stocks that began in November after a long string of broader exposure. The IMX fell to 5.48 in December, from 5.53 in November and a two-year high of 5.83 in October.But that isn’t really the full story. In fact, TD Ameritrade clients were actually net buyers in December, even as their exposure to stocks declined minimally. Why, then, did the overall number fall? It didn’t seem related to any lack of interest in the stock market, which recorded new record highs. Instead, the drop appeared to reflect lower relative volatility in some widely held names like Apple Inc. and General Electric Company .Read more